Balanced spring hammer magnetic type



April 18, 1933- F. SCHOUTEN 1,904,955

BALANCED SPRING HAMMER MAGNETIC TYPE Filed Feb. 7, 1931 3 Sheets-Sheet 1 w iiiw &

April 18, 1933. SCHOUTEN 1,904,955

BALANCED SPRING HAMMER MAGNETIC TYPE Filed Feb. 7, 1931 3 Sheets-Sheet 2 April 18, 1933. F. SCHOUTEN ,9

BALANCED SPRING HAMMER MAGNETIC TYPE Fi e 1951 5 Sheets-Sheet 3 Patented Apr. 18, 1933 UNITED STATES PATENT, OFFICE FRANK SCHOUTEN, OF GLENABM, MARYLAND, ASSIGNOR TO THE BLACK & DECKER MANUFACTURING COMFANY, 0F TOWSON, -MARYLAND, A CORPORATION OF mm LAND BALANCED SPRING HAMMER MAGNETIC TYPE Application filed February 7, 1931. Serial No. 514,176.

The invention relates to an electrically operated mechanical hammer of the magnetic type in'which a solenoid or electromagnet, which may be of the standard conventional design, operates a solenoid plunger or core which, instead of striking directly on the anvil, is connected to a ram by means of a spring or springs, preferably balanced springs, the natural period of vibration of the springs and ram being in. the preferred form of the invention an. inte ral function of the period of reciprocation o the solenoid plunger, which is in turn determined by the frequency of the current in connection with which the hammer is adapted to be used or the current changes applied to the solenoid and other conditions of operation.

Applicants hammer, as constructed, may be treated as an example of the preferred form of the invention. This hammer or type of hammer is adapted for use with a rectified current or other pulsating current having a frequency of 7200 pulsations per minute. With this current a speed of reciprocation is imparted to the plunger which gives 3600 strokes a minute. The frequency of the current pulsations is, to a large degree, dependent upon the supply of current available, though this may be stepped up and down by a well-known apparatus to give the desired frequency, and the frequency may further be changed by adjustment to accord with or vary from the natural period of vibration of the spring and ram, to vary the force of the blow at the will of the operator.

In order to obtain the desired results, it is desirable that the movement of the solenoid plunger or core be stopped at certain definite points, and for this reason relief or stop springs are located at each end of the path of the plunger to bring the plunger to a stop at each end of its stroke, the kinetic energy of the ram and springs being transferred to the bit or tool.

In the accompanying drawings I have illustrated a hammer of the solenoid balanced vibratory spring type in several dif- In the drawings- Figure 1 is a vertical longitudinal section on the axis of a hammer or reciprocating tool of this type embodying the invention, the same being broken away near the centre of the barrel for convenience of illustration.

Figure 2 is a similar section of the lower end of the tool, this figure being continuous with Figure 1,

Figure 3 is a section on the line 3, 3 in Figure 2.

Figure 4 is a complete longitudinal axial section of a modified form of the hammer in which substantially the entire reciprocaticpg mechanism is mounted within the sole- I101 Figure 5 is a view showing the ram, and a plunger or core in the form of a'rin of magnetic material surrounding the ram, t ese parts being removed and separated from the remainder of the construction, the ram having a spring casing formed integral with the ram.

Figure 6 is a transverse section on the line 6, 6 of Figure 4.

Figure 7 shows a somewhat different arrangement of the essential parts, the solenoid plunger in this instance being rigidly attached to the spring chamber of the ram which it encircles, being shown as located near the centre.

Figure 8 is a transverse section on th line 8, 8 of Figure 7.

Figure 9 is a section'through a spring casing and solenoid plunger or core, taken on the axis of the latter, the ram being somewhat difierent from that of Figure 7 and Figure 10 is a circuit diagram showing a convenient manner of connecting the solenoid coils to a pulsating current which is preferably rectified for this purpose, whereby the circuit Within the solenoid cores is subjected to the desired pulsations, in accordance with the well-known practice, giving a reciprocating action of the plunger or core without necessity for any mechanical means for making and breaking the circuit.

Referring to the drawings by numerals, each of which is used to indicate the same or similar parts in the different figures, the

construction shown, particularly in Figures 1, 2 and 3, consists of two solenoid coils 1 and 2 of conventional design and arrangement, placed end to end, and enclosed within an outer shell or casing 3 known as the solenoid casin In the preferred form of the invention s own, the solenoid coils 1 and 2 are wound about or otherwise enclose a guiding tube 4 of non-magnetic material, in which I the core or plunger 5 is slidably mounted.

This plunger is in turn secured to a piston rod 6 which extends downwardly through a suitable openin 7, into the spring casing 8 of the ram 9, ing secured at its lower end to the balanced spring abutment 10 which is mounted in the casing 8 and freely movable therein, being supported between the balanced springs 11 and 12, which are compressed between the centre abutment 10 and the ends of the casing at 14 and 15, hereinafter referred to as end abutments, the latter being thickened to serve as the striker end of the ram. The ram in turn is mounted to reciprocate within a suitable hammer barrel 16, which is of suitable length and provided at its lower end with a tool bushing 17 for the tool or hit 18.

The solenoid casing 3 is shown as having a threaded connection 19 with the hammer barrel 16, and the lower.v end of the solenoid casing is closed by means of a plate 20 which as shown is secured between the solenoid casing and the barrel and within the upper enlarged end of the latter, being supported on a suitable shoulder 21 in the barrel just below the threaded portion 22.

The guiding tube 4, as shown, is closed at one end by the upper end of the solenoid casing 3 and at the other end by the plate 20, and located within this tube at each end are stop springs 24 and 25, suitably secured, which contribute to the desired result by stopping the core 5 or arresting its motion at definite predetermined points at the ends of its stroke when the kinetic energy of the ram and springs and the plunger 5 is transfcrred by the ram to the tool or hit 18.

In Figure 10 I have illustrated a circuit diagram adapted to energize the solenoid in the construction, Figures 1, 2 and 3, or in any of the various constructions shown, tho i h various different typesof circuit may be utilized for this purpose to supply the necessary current changes to the solenoid.

In accordance with the circuit diagram, Figure 10, the coils 1 and 2 of the solenoid are connected to a pulsating direct current which is ordinarily obtained by rectifying an alternating current. In the preferred arrangement, the adjacent ends of the coils 1 and 2 are connected to a common return wire .27, and the ends of these coils 1 and 2, which are remote from the return connection 27, are each connected as by wires 28 and 29 to the positive side of the line supplying the rectified or other pulsating current.

As already ointed out, a pulsating current thus supp ied to the solenoid coils having 7200 pulsations a minute, causes 3600 strokes or reciprocations of the plunger 5 whereby the ram is vibrated at a corresponding speed, the number of strokes per minute being equal to the number of strokes of the core or any integral function thereof, dependin upon the natural period of vibration 0 the springs and ram, as already pointed out, and the frequency of the current, which may, if desired, be varied by suitable step-up apparatus 23, well known in the art, which may be part of the electrical equipment of the plant in which the tool is operated.

As already pointed out, the stroke of the plunger 5, and hence of the sprin abutment or piston 10, is stopped or arreste at definite points by means of the relief or stop springs 2%, 25, and the resulting reciprocation of the solenoid plunger 5 timed with the ulsations or changes of the current, as alrea y pointed out, is communicated through the reciprocating piston or spring abutment 10 through the balanced springs 12 and 11 to the ram 9, which is shown in this construction as integral with the spring casing 8, the most efiicient o ration of the hammer, as already inte out, being obtained when pulsations o the current and hence the strokes of the plunger 5 are equal to or an even function of the natural period of vibration of the springs and ram.

Figures 4, 5 and 6 illustrate a modified and further developed arrangement of the mechanism, in which substantially the entire reciprocating mechanism, includin the bulk of the ram and spring casing, whic is auxiliary to the solenoid, is enclosed or encompassed within the solenoid. In this construction the solenoid core or plunger 30 is in the shape of a ring of suitable magnetic material surrounding the spring casing 31 which is integral with and forms a portion of the ram 32 within which casing are mounted the balanced springs 33 and 34, being compressed between the ends of the casing and a central abutment or piston 35. In the construction shown a pin 36 is passed through the piston or central abutment 35 and seated at its two ends in the plunger ring 30, the spring casing 31 of the ram being slotted longitudinally on both sides at 37 to form ways for the pin providing for 1 and permitting the reciprocation of the same, and the hammer casing or barrel is enlarged centrally, forming an annular chamber 38 surrounding the central position of the ram or more particularly the spring casing 31 within which the solenoid coils 39 and 40, comprising the solenoid 41, are enclosed, the solenoid being provided, as in the previous instance, with a guiding tube 42 of non-magnetic material in which the solenoid plunger or core 30 reciprocates, so that the tube 42 of non-magnetic material acts as a guide for the same. As in the previous instance, the guiding tube 42 contains stop springs 43 and 44 at its respective ends, which serve to stop or arrest the plunger or magnet 30, and hence the abutment or piston 35 at certain definite points, determining with almost positive accuracy the stroke of the plunger and the piston or balanced spring abutment 35.

In the form of the invention shown, particularly in Fi ures 4 and 5, the ram 32, including the spring casing 31, is guided within a barrel 45, which is discontinued at the centre and separated into spaced sections 46 and 47, which are connected and supported at the centre and partially enclosed by the easing 38 already described, as containing the solenoid 41, comprising the coils 39 and 40. The spacing of the barrel sections 46 and 47 provides a path for the solenoid plunger 30 which reciprocates between said sections 46 and 47 guided by tube 42. This spacing of the barrel sections also permits the solenoid plunger to immediately overlie the spring casing which is integral with the ram and to which it is operatively connected by the abutment 35 and springs 33 and 34, the abutment 35 being carried directly on the plunger by means of pin 36. The springs 33 and 34 in turn serve to transmit the motion of the spring abutment or piston 35 to the ram in the manner already described in connection with the construction of Figures 1, 2 and 3.

The important feature of the arrangement shown in Figures 4, 5 and 6, and described in connection therewith, is that it serves to shorten the hammer to a very considerable extent as compared to the construction of Figures 1, 2 and 3, in which the barrel 16 is secured to the end of the solenoid casing 3, with the solenoid coils 1 and 2 therein, the reduction of the overall length being due to the inclusion of the spring casing 32, the springs 33 and 34 and abutment 35 within the solenoid.

Figures 7, 8 and 9 show a different arrangement of the actuating parts of the tool,

in which the operating parts are again enclosed within the solenoid core, producing a shorter and more compact hammer as compared to the construction Figure 1, and more closely resembling the construction Figures 4, 5 and 6'except as to the specific arrangement of the core of the ram and of the balanced springs, as hereinafter more specifically described.

In this construction there is a tool casing 50 comprising a barrel 51 consisting of two sections 52 and 53 spaced in the direction of the stroke, whereby the spring casing 54 is guided in its reciprocating motion, and a central enlarged portion 55 containing and supporting the solenoid coils 56 and 57 in a position in which they surround the casing 54. This enlarged portion or coil casing 55 serves to support and connect the sections 52, 53 of the barrel 51, between which sections the solenoid plunger or core 58 is mounted to reciprocate in a guiding tube 59 of nonmagnetic material within the solenoid coils. The movement of the plunger 58 is arrested at definite points at the ends of its stroke by stop springs 60 and 61. enclosed within the tube 59 and bearing against shoulders 62 formed on the inner ends of the barrel sections 52 and 53.

The solenoid core or plunger 58, in the form of a ring of magnetic material encircling the ram, is attached to the spring casing 54 in any suitable manner as by means of screw-threads 65 formed on the inside of the plunger ring and on the outside of the spring casing. The spring casing contains balanced springs 66 and 67, and an abutment or piston 68 supported between the balanced springs. In the form of the invention shown this piston or abutment is guided by means of a piston rod 69 extending through a suitable guide bearing 70 in the upper end of the spring casing, the said upper end being shown in the form of a removable screwplug 71. The ram 72, as shown, is secured to the piston or spring abutment 68, being shown in Figure 7 as formed integrally with the piston rod 69, the integral'structure 69, 72 being slightly enlarged an threaded at 73 just above the ram 72 which is of larger diameter than the piston rod 69 and engaged in a suitable threaded opening 74 in the spring abutment or piston 68.

Figure 9 shows a slightly different alternative structure in which the spring abutment 76 is in the form of an annular shoulder formed at the centre of an integral ram 77 consisting of a guiding member or piston rod 78 which projects rearwardly or upwardly through the upper end of the spring casing 79 in which it has a suitable guide bearing 81. and a striker member 80 which pro jects through the opposite end of the spring casing 79 and in which it has a guide bearing at 82. The spring casing is shown as formed in two similar sections 81 and 82 connected together by threading their open ends into the corresponding threaded plunger ring 83. Balanced springs 84 and 85 hear at their outer ends against the corresponding ends of the casing 79, and at their inner ends against the spring abutment shoulder or collar 76.

In both instances, i.e., constructions of Figures 7 and 9, the ram member reciprocates through and relatively to the spring casing, be ng controlled in its relation thereto by the balanced springs 66 and 67 in one instance. and 84 and 85 in the other instance, and by the pulsations of the current in the solenoid and the corresponding reciprocations of the solenoid plunger, the natural period of vibration of the springs and ram in each instance being preferably an integral function of the current pulsations, and hence of the speed and period of reciprocation of the plunger whereby the speed and period of reciprocation of the ram is determined and the most efiicient operation of the hammer results.

I have thus described specifically and in detail the various embodiments of the solenoid type of balanced spring hammer embodying the features of my invention in order that the manner of constructing the same, and applying. operating and using the invention may be clearly understood. However. the specific terms herein are used descriptively rather than in a limiting sense. the scope of the invention being defined in the claims.

What I claim as new and desire to secure by Letters Patent is:

1. The combination in a portable powerdriven hammer of a solenoid. having a core. means for energizing the solenoid periodically to reciprocate the core. a ram. means for guiding the ram. and balanced spring means connecting the ram to the core whereby the reciprocating motion of the core is imparted by the spring to the ram.

2. The combination in a portable powerdriven hammer of a solenoid having a core. means for energizing the solenoid periodically to reciprocate the core, a ram. means for guiding the ram in a path parallel to the path of the core. balanced springs connecting the ram to the core whereby the reciprocating motion of the core is imparted to the ram with a frequency which is a function of the frequency of the reciprocations of the core and the natural frequency of vibration of the spring and ram. and stop springs for controlling the stroke of the solenoid core at each end.

3. The combination in a portable powerdriven hammer of a solenoid. a core for the solenoid. means for energizing the solenoid periodically, and producing current changes therein to reciprocate the core. a. ram. and means for communicating the reciprocations of the core to said ram. including opposed balanced springs.

4. The combination in a portable power hammer of a solenoid and core. means for energizing the solenoid and producing periodic current changes therein to vibrate the core. balanced springs and a spring abutment rigidly connected to the core for communicating the vibrations of the core to the springs, and a ram to which the vibrations of the core are communicated through and by way of the balanced springs.

5. The combination in a portable power hammer of a solenoid and a core. means for energizing the solenoid and producing periodic current changes therein to vibrate the core, balanced springs and a spring abutment rigidly connected to the core for communicating the vibrations of the core to the springs, and a ram to which the vibrations of the core are communicated through and by way of the balanced springs. and resilient means for limiting and determining the stroke of the core.

6. The combination in a portable powerdriven hammer of a solenoid. means for en ergizing the same producing periodic current changes therein. a core co-operating with the solenoid and reciprocated by and in response to said current changes. a spring casing secured to the core. said casing being provided with spaced abutments and balanced springs compressed between the abutments. a piston between said springs. and a ram operated by said piston through and by way of the balanced springs.

7. The combination in a portable powerdriven hammer of a solenoid. means for energizing the same producing periodic current changes therein. a core cooperating with the solenoid and reciprocated by and in response to said current changes. a spring casing encircled by and secured to the core. said casing being provided with spaced abutments and balanced springs compressed between the abutments. a piston between said springs and a ram operated by said piston through and by way of the balanced springs. and resilient means for limiting the stroke of the core.

8. A combination in a portable powerdriven hammer of a solenoid. a core. means for energizing the solenoid. and producing periodic changes therein to reciprocate the core. a spring casing secured to the core and enclosed within the solenoid. opposed balanced spring means therein. a spring abutment supported by the spring means. and a. ram rigidly connected to said abutment to be operated by and through said spring means from said core.

9. The combination in a portable powerdriven hammer of a solenoid. a core, means for energizing the solenoid and producing current fluctuations therein to reciprocate the core, a spring casing and balanced springs therein enclosed within the solenoid and including a. ram connected to the casing. and a spring abutment between said springs rigidly connected to the core for communicating the vibrations of the core through said springs and to said ram.

10. The combination in a portable powerdriven hammer of a solenoid and core. a noncondncting tubular guide for the core within the solenoid. means for energizing the solenoid. and producing current changes therein to reciprocate the core, spring stops at each end of the tube to limit the motion of the core. aspring casing. and balanced spring means therein having an abutment at each end and an abutment supported intermediately of said spring means, part of said abutments being secured to said core, and a ram to which the remainder of said abutments is secured, the ram bein likewise enclosed within the solenoid w ereby 5 the motion of the core is communicated by and through the springs to the ram.

11. The combination in a portable powerdriven tool of a solenoid, a core for the solenoid in the form of a ring, means for producing periodic current changes in the solenoid to reciprocate the core, a spring casing encircled by the core and secured therein, balanced springs inside the casing and a spring abutment between the springs which are compressed within the casing, and a ram secured to said spring abutment to be operated thereby and also enclosed within the solenoid.

12. The combination in a portable powerdriven tool of a solenoid having a core, means for energizing the solenoid and producing periodic current changes therein to reciprocate the core, a spring abutment secured to the core, a ram having spaced spring abut ments, and spring means compressed between said spring abutments, the spring abutment carried by the core being supported intermediately of said spring means whereby the motion of the core is communicated to the ram through said spring means.

13. The combination in a portable powerdriven tool of a solenoid having a core in the form of a ring, means for energizing the solenoid and producing periodic current changes therein to reciprocate the core, a spring abutment secured to the core, a ram having spaced spring abutments and enclosed spring means compressed between said spring abutments, the spring abutment carried by the core being supported intermediately of said spring means, whereby the motion of the core is communicated to the ram through said spring means, the natural period of vibration of the spring means and ram be ing an integral function of the speed of vibration of the core and the period of current change.

14. The combination in a portable powerdriven tool of a solenoid having a core in the form of a ring, means for energizing the solenoid and producing periodic current changes therein to reciprocate the core, a spring abutment secured to the core, a ram having spaced spring abutments and enclosed springs compressed between said spring abutments and encircled by the core and by the solenoid, the spring abutment carried by the core being supported between said springs whereby the motion of the core is communicated to the ram through said springs.

Si ned by me at Towson, Baltimore County, aryland, this 4th da of February, 1931,

FRA K SCHOUTEN. 

